• Journal of Korean Society on Water Environment
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• v.25 no.3
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• pp.432-440
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• 2009

The effect of selecting hydrologic item for calculating objective function on calibration of stream flow was evaluated by Hydrologic Simulation Porgram-Fortran (HSPF) linked with Model Independent Parameter Optimizer (PEST). Daily and monthly stream flow and flow duration were used to calculate objective function. Automated calibration focused on monthly stream was proper to analyze seasonal or yearly water budget but not proper to predict daily stream flow or percent chance flow exceeded. Calibration result focused on flow duration is proper to predict precent chance flow exceeded but not proper to analyze water budget or predict peak flow. These results indicate that hydrologic item calculated for objective function on calibration procedure could influence calibration results and watershed modeler should select carefully hydrologic item for the purpose of model application. Current, the criteria of stream flow of Korean TMDL is generated based on percent chance flow exceeded, so flow duration should be included to calculate objective function on calibration procedure for the estimation of criteria of stream flow using hydrologic model.

• Journal of Ocean Engineering and Technology
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• v.29 no.4
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• pp.283-290
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• 2015

This paper presents the results of a numerical study on the towing characteristics of a barge under various wind conditions. First, stability criteria, including the wind force, were derived based on the linear motion equations of a towed vessel. The effect of the wind force on the towing stability was investigated using stability criteria. Next, towing simulations were carried out using a nonlinear time-domain simulation method. In this case, the towline was modeled as a simple spring-damper, and the wind force was computed using the wind coefficient from CFD calculations. Simulations were conducted for a barge under a constant towing speed and constant wind speed conditions. The effect of the wind direction on the slewing motion was also observed. In addition, a series of numerical simulations using variable wind speeds were performed for the present barge with and without a skeg.

• Architectural research
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• v.4 no.1
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• pp.1-6
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• 2002

Every year new tall buildings are being conceived, designed, and built with new schemes. Thus it is important to explore the factors that affect tall building design. Thus it is important to explore the tall building design factors. The planning and design of tall buildings require different criteria than those that exist in regular size buildings. Tall buildings are uniquely expressed by their structural systems where exterior esthetic and requirements of space drive the form and composition of the structural systems. Therefore the exploration of design factors is the key to achieve optimum building systems. Optimization as mentioned here is associated with the efficiency of the different building systems. To achieve an optimal system, there is a need for an understanding of the factors that affect on overall tall building design such as planning module, building function, lease span, floor-to-floor-height, building height (aspect ratio), structural system, environmental systems. In this paper a statistical approach will be used and will be based on data collected from the practice through a rigorous survey taken. This information is tabulated and analyzed. The major target of investigation will be lease span related to space requirement in the tall building planning. Factors related to lease spans, such as function, floor-to-floor height, planning module, building height, overall plan dimension, and plan ratio (building geometry), will be looked at carefully. IN conclusion, this approach of optimization can introduce a preliminary design guideline for tall building projects. The purpose of the paper should shed some light on the optimum tall building design criteria.

• Clinical and Experimental Pediatrics
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• v.59 no.sup1
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• pp.152-156
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• 2016

Megalencephaly-capillary malformation-polymicrogyria syndrome (MCAP), previously known as macrocephaly-cutis marmorata telangiectatica congenita and macrocephaly-capillary malformation syndrome, is a rare multiple-malformation syndrome that is characterized by progressive megalencephaly, capillary malformations of the midline face and body, or distal limb anomalies such as syndactyly. Herein, we report a female infant case that satisfies the recently proposed criteria of MCAP and describe the distinctive neuroradiological and morphological features. We have also reviewed recently published reports and the diagnostic criteria proposed by various authors in order to facilitate the clinical diagnosis of these children in pediatric neurology clinics.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.9 no.3
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• pp.31-38
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• 1989

This paper concentrates on the analysis of reinforced concrete(R/C) structures subjected to monotonic loading, from zero to ultimate loads. Tensile cracking, the nonlinear stress-strain relationship for concrete and reinforcement are taken into account the concrete is assumed to be elastic in tension region and elasto-hardening plastic in compression region. The Kupfer's failure criteria and associated flow rule are adopted to govern the plastic behavior of the concrete. The reinforcing bar is considered as a elasto-hardening platic material. The tension stiffening effect of the concrete between cracks is also considered. The numerical error depends on the used finite element mesh size is reduced by correcting the slope of strain softening region of the concrete according to the developed energy criteria.

• Journal of Korean Foot and Ankle Society
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• v.10 no.2
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• pp.184-189
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• 2006

Purpose: To evaluate surgical treatment using two-staged MIPO technique in tibial pilon fractures involving tibial shaft. Materials and Methods: Twelve patients, who underwent two-staged MIPO technique for pilon fractures involving tibial shaft between January 2003 and May 2005, were followed for more than one year. Radiographs were graded by the criteria of Anglen and ankle functions were graded by the criteria of Mast and Teipner. Ankle function, union time and postoperative complications were also analysed. Results: Clinically there were eight (67%) good results, three (25%) fair results and one (8%) poor result. At the last follow-up, the radiographic results showed seven (58%) excellent results, three (25%) good results, and two (17%) fair results. During the follow up, There was one case of nonunion Conclusion: Two-staged MIPO techinque is one of the good methods for the treatment of pilon fractures invloving tibial shaft.

• Journal of Environmental Impact Assessment
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• v.11 no.2
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• pp.93-107
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• 2002

The choice of big public investment project needs an appropriate feasibility analysis before it is implemented, bemuse a rot wisely chosen one would bring about big and longrun societal costs. But the feasibility analysis for the big public investment project in Korea has been done without linking the economic benefits and environmental damages. Consequently social conflicts arose frequently during and after project implementation, owing to such concerns asincreasing costs and serious ecological damages. The recent social conflict over the Saemangeum Project is a typical case. This reclamation project began in 1991 and finished 60% of the whole process in 1999, when its feasibility was again assessed under the public pressure by the joint assessment team consisting of both citizen's and government's professionals. Even the assessment report by this joint team could not show the convincing results owing to the improper assessment procedure and failure to set proper feasibility criteria. This paper pointed out the limitations of our current procedure of feasibility assessment and identified the concrete problems that atosee during the recent reassessment process of the Saemangeum reclamation project by the joint team. In order to improve the current problem-ridden practices, it is concluded by the policy recommendation for establishing a right feasibility assessment procedure for the public investment projects.

• Transactions of Materials Processing
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• v.15 no.3 s.84
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• pp.220-225
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• 2006

This paper investigates the characteristics of a hydro-mechanical punching process. The hydro-mechanical punching process is divided into two stages: the first stage is the mechanical half piercing in which an upper punch goes down before the initial crack is occurred; the second stage is the hydro punching in which a lower punch goes up until the final fracture is occurred. Ductile fracture criteria such as the Cockcroft, Brozzo and Oyane are adopted to predict the fracture of sheet material. The index values of ductile fracture criteria are calculated with a user material subroutine, VUMAT in the ABAQUS Explicit. The hydrostatic pressure retards the initiation of a crack in the upper region of the blank and induces another crack in the lower region of the blank during the punching process. The final fracture zone is placed at the middle surface of the blank to the thickness direction. The result demonstrates that the hydro-mechanical punching process makes a finer shearing surface than the conventional one as hydrostatic pressure increases.

• Journal of Korean Society on Water Environment
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• v.25 no.6
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• pp.964-971
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• 2009

In this paper, activated sludge settling was characterized based on field trip and zone settling tests. Plants used for this study include 5 conventional activated sludge processes and 3 A2O type treatment processes. The treatment capacities are in the range from 12,000 to $250,000m^3$/day. Total number of zone settling tests were 188 set and SVI values representing settling characteristics were from 100 to 300 mL/g. It was found out that zone settling velocity of these examined plant sludges can be approximated by mean values calculated by Keinath and Daigger/Roper models. Based on these three models, solid flux analysis were carried out in order to compare design criteria ($3.96{\sim}6.04kg/m^2-hr$) recommended by Korea Sewage Facility Design Guideline with two models used in USA. The results show that design criteria are only applicable for normal condition in settling characteristics (below SVI 100 mL/g). Solid flux analysis of surveyed plants indicates that most of the plants are operated underload conditions except several plants experiencing poor sludge settling problem. Most of the plants are operated under high sludge blanket depths (SBD).

• Journal of the Korean Society for Precision Engineering
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• v.23 no.5 s.182
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• pp.177-183
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• 2006

A tape feeder is an important feeding device to supply micro-chips such as 1005 and 0603 components to PCB in SMT process. Traditionally, tape feeding methods using sprocket wheel mechanism has been used for the pickup system of chip-mounters. However, there is growing needs for new feeding mechanism with high accuracy and confidence as electric components are getting much smaller. Thus, recently, a tape feeder using cam-slider mechanism is developed to meet such requirements. The major advantages of developed system are; significantly reduced indexing and backlash errors, slim and compact design, and improved repetitive capacity compared to existing system. In this paper, the performance evaluation criteria for the developed tape feeder are suggested. Stability against induced vibration, positioning accuracy, cycle time, durability and supply error rate are estimated using developed self testers. As a result, the excellence of developed tape feeding mechanism is validated using the effective rating methods.